Fluid pressure motor



June26, 1945. Y, w, H. GLAss l 2,379,291

-FLUID PRESSURE MOTOR Filed March 51, 1943 'I INVENTO WlliamHLass BY imATTORN EY Patented June 26, 1945 FLUID PRESSURE MOTOR William H. Glass,Pittsburgh, Pa., assigner to The Westinghouse Air Brake Company,Wilmerding, Pa., a corporation of Pennsylvania l Application March `31,1943, Seal No. 481,195

3 claims. (o1. 121-48) This invention relates to fluid pressure motorsand more particularly to the type employing movable actuating abutmentsin the form of ilexible diaphragme.

Flexible disk like diaphragms made from rubber composition and havingmolded therein 'suitable reinforcing fabric having been developed tokwithstand high uid pressures such as encountered in certain fluidpressure controlled devices. In fluid pressure motors diaphragms of thistype have been advantageously employed where it is desired to obtainmovement of a control element upon small variations in control pressure.Unlike ringed pistons however, the movement or deflection of suchdiaphragms must be limited in order to avoid the overstressing of thediaphragms and possible consequent premature failure thereof. Where itis desired to move a control element a greater distance than ispracticable to attain by the deflection of an operating diaphragmwithout danger of damage to the diaphragm, it has been necessary toresortto a ringed piston and due to the friction between the ring andthe bore in which it operates, variations in the increments of pressurefor operation must necessarilyv be increased.

The principal object of the invention is the provision of an improvediluid pressure motor of the diaphragm type which operates on smallvariations in pressure and which is so constructed as to provide for thelong travel of the element to be actuated without overstressing thediaphragm structure.

Other objects and advantages will appear from the following moredetailed description of the invention.

In the accompanying drawing, the single figure is a sectional viewshowing a uid pressure motor embodying the invention.

As shown in the drawing the fluid pressure motor may comprise ahorizontally disposed casing portion I having a pair of spaceddownwardly projecting body portions 2 and 3 which are open at oppositeends, and may further comprise a pair of cap members 4 and 5for closingthe open ends of the body portions 2 and 3, respectively.

Clamped between the body portion 2 and the cap member 4 is a flexiblediaphragm 6 and clamped between the body portion 3 and the cap member 5is a similar fiexible diaphragm 1, which diaphragms in the presentembodiment of the invention have been shown as being of substantiallythe same area.

At one side of diaphragm 6 there is a chamber Ill and at one side ofdiaphragm 1 there is a chamber II which chambers are connected togetherby means of a passage I2 which in turn is connected'to a pipe I4,

At the opposite side of diaphragm 6 there is a chamber I5 and at theopposite side of diaphragm 1 there is a chamber I6 which chambers are inconstant open communication with the atmosphere by way of passages I1and I8, respectively.

-The diaphragm 6 is clamped between a diaphragm follower contained inchamber I5 and a diaphragm follower 2| contained in chamber I0 at theopposite side of the diaphragm, by means of nut 22 havingscrew-threadedconnection with a stud portion 23 carried at one end of astem or rod `24, which stud portion passes through a suitable centralopening in the followers 20 and 2|. The stem or rod 24 passes throughchamber I 5 and extends through a suitable opening in the end wall ofthe chamber to the exterior thereof. Contained in chamber I5 andsurrounding the stem or rod 24-is a spring 25 which, at all times, tendsto urge the 'diaphragm assemblage including diaphragm 6, follows 20 and2l and stem or rod 24 in a direction toward the left hand as viewed inthe drawing.

The diaphragm 1 is clamped between av diaphragm follower 21 contained inchamber. lIl' and a diaphragmfollower 28 containedin chamber II at theopposite side of the diaphragm, by means of a nut 29 havingscrew-threaded connection with a stud portion 30 carried at one end of astem or rod 3l, which stud portion passes through a suitable centralopening in the followers 21 an'd 28. The stem or rod 3l passeshorizontally through chamber I6 and extends through a suitable openingin the end wall of the chamber to the exterior thereof. Contained in thespace between the body portions 2 and 3. The

lever 31 is provided with a slotted opening 38 which extendslongitudinally of the lever and is disposed nearer to the end of thelever connected to the jaw 35 than to the opposite end of the lever.Contained in the slotted opening 38 of the lever 31 is a pin 40 which iscarried by a jaw 4I provided at the outer end of the stem or rod 3l.

In use, with chambers I and II at atmospheric pressure the springs 25and 32 act to maintain the diaphragm assemblies in the body portions 2and 3, respectively, and thereby the lever 31, in the position in whichthey are shown in the draw- If fluid under pressure is supplied to pipeI4 it flowstherefrom to chambers I0 and Il by Way of passage I2. Fluidunder pressure thus supplied to chamber I0 acts on diaphragm 6 inopposition to that of spring 25 and fluid under pressure supplied tochamber I I acts on diaphragm 1 in opposition to that of spring 32. Whenthe pres-'- sure of fluid in these chambers and acting on diaphragm 6and 1 has been increased to a degree suilicient to overcome the opposingforce of springs 25 and 32 the diaphragm 6 will be caused to deflect ina direction toward the right hand while the diaphragm 1 will be causedto deflect in a direction toward the left hand.

The diaphragm 6 as it deflects in a direction toward the right hand,causes the rod 24 to move in the same direction, and the diaphragm 1 asit deects in a direction toward the left hand, causesthe rod 3| to movein the same direction. As therods 24 and 3l are thus moved in oppositedirections, the force transmitted through the rods acts on oppositesides of the lever 31 causing said lever to pivot about the pins 38 and40 to actuate the lever 31 in a clockwise direction.

It should here be noted that both diaphragms -operate to move the rods24 and 3| in opposite directions, and since the rods are operativelyconnected to the lever at different positions along its length eachdiaphragm as it is deflected functions to increase the distance oftravel of the lever 31. From this it will be seen that the distance oftravel of the lever Will be-considerably greater than the distance eachdiaphragm deects. By reason of this arrangement pistons or impracticablediaphragms need not be resorted to in order to move the lever arelatively long distance.

When fluid under pressure is released from chambers I0 and II by way ofpassage I2 and pipe I4 the springs 25 and 32 act to cause the diaphragms6 and 1 to deflect in opposite directions to thereby move the rods 24and 3| and the connected lever 31 to the position in which they areshown in the drawing.

under pressure simultaneously thereto, means forv conducting pressurefluid simultaneously to the diaphragms, a floating lever, meansI foroperatively connecting one of said diaphragms to said lever at one placebetween the ends of the lever, and other means for operativelyconnecting the other of said diaphragms to said lever at a differentplace between the ends of said lever both of said means being operativeupon a deflection of said diaphragms for actuating said lever.

2. A fluid pressure motor comprising a casing having a pair of spacedbody portions, a pair-'of flexible diaphragms, one of said diaphragmsbeing disposed in one of said body portions and being arranged fordeflection in one direction the other of said diaphragms being disposedin the other of said body portions and being arranged for deflection inthe opposite direction upon the sup-y ply ofvuid under pressuresimultaneously thereto, means for conducting pressure fluidsimultaneously to the diaphragms, a floating lever having one of its endportions extending into the space between said body portions, and meansoperatively connecting said'diaphragms to said end portion of the leverat different places in the direction of the length of the lever, saidmeans being operative upon deflection `of said di aphragms for actuatingsaid lever. Y

3. A fluid pressure motor comprising a casing, a pair of flexiblediaphragms disposed in said casing and provided for deflection in adirection toward each other upon the supply of fluid under pressuresimultaneously thereto, means for conducting pressure fluidsimultaneously to the diaphragms, a floating lever having one end"portion disposed between said diaphragms, and means operativelyconnecting said diaphragms to said lever` for effecting actuation 0fsaid lever upon deflection of said diaphragms. I

WILLIAM H. Grass.l

